--- name: "visir_util_undistort" section: "7" platform: "linux" package: "cpl-plugin-visir-doc" version: "4.4.2+dfsg-1" release: "Debian 12 (Bookworm)" platforms: ["linux"] url: "https://new.carta.tech/visir_util_undistort" --- # visir\_util\_undistort(7) Correct the distortion in spectral data ## NAME visir\_util\_undistort - Correct the distortion in spectral data ## SYNOPSIS esorex **visir\_util\_undistort** \[OPTIONS\] FILE.sof ## DESCRIPTION The files listed in the Set Of Frames (sof-file) must be tagged: VISIR-chopnod-corrected-file.fits CHOPNOD\_CORRECTED Optionally, a bad pixel map may be provided: VISIR-bpm-file.fits STATIC\_MASK The product(s) will have a FITS card ´HIERARCH ESO PRO CATG´ with a value of: UNDISTORTED The recipe default values for the transformation are only valid for spectral data taken in Low resolution mode ## OPTIONS - **--bkgcorrect** *\* Cho-nod correct the data (bool; default: True). The full name of this option for the EsoRex configuration file is **visir.visir\_util\_undistort.bkgcorrect** \[default = *True*\]. - **--xl** *\* Coordinate in spatial direction. Together with yl it defines the lower point of a rectangle containing only skylines for the wavelength shift detection (int; default: 117). The full name of this option for the EsoRex configuration file is **visir.visir\_util\_undistort.xl** \[default = *117*\]. - **--yl** *\* Coordinate in wavelength direction. See xl (int; default: 110). The full name of this option for the EsoRex configuration file is **visir.visir\_util\_undistort.yl** \[default = *110*\]. - **--xh** *\* Coordinate in spatial direction. Together with yl it defines the higher point of a rectangle containing only skylines for the wavelength shift detection (int; default: 125). The full name of this option for the EsoRex configuration file is **visir.visir\_util\_undistort.xh** \[default = *125*\]. - **--yh** *\* Coordinate in wavelength direction. See xh (int; default: 150). The full name of this option for the EsoRex configuration file is **visir.visir\_util\_undistort.yh** \[default = *150*\]. - **--slit\_skew** *\* Distortion correction: Skew of slit (degrees) (clockwise) (float; default: 0.52). The full name of this option for the EsoRex configuration file is **visir.visir\_util\_undistort.phi** \[default = *0.52*\]. - **--spectrum\_skew** *\* Distortion correction: LMR Skew of spectrum (degrees) (counter- clockwise). Not used in High Resolution (float; default: 1.73). The full name of this option for the EsoRex configuration file is **visir.visir\_util\_undistort.ksi** \[default = *1.73*\]. - **--vert\_arc** *\* Distortion correction: LR Detector vertical curvature (pixel). Reduced by a factor 4 in MR. Not used in HR A-side. Increased by a factor 115/52 in HR B-side (float; default: -0.8). The full name of this option for the EsoRex configuration file is **visir.visir\_util\_undistort.eps** \[default = *-0.8*\]. - **--hori\_arc** *\* Distortion correction: LMR Detector horizontal curvature (pixel). Increased by a factor 1.5 in HR A-side. Reduced by a factor 2 in HR B-side (float; default: 0.0). The full name of this option for the EsoRex configuration file is **visir.visir\_util\_undistort.delta** \[default = *0.0*\]. Note that it is possible to create a configuration file containing these options, along with suitable default values. Please refer to the details provided by the 'esorex --help' command. ## SEE ALSO The full documentation for the visir pipeline can be downloaded as a PDF file using the following URL: - **ftp://ftp.eso.org/pub/dfs/pipelines/visir/visir-pipeline-manual-1.4.pdf** An overview over the existing ESO pipelines can be found on the web page **https://www.eso.org/sci/software/pipelines/**. Basic documentation about the EsoRex program can be found at the esorex (1) man page. It is possible to call the pipelines from python using the python-cpl package. See **https://packages.python.org/python-cpl/index.html** for further information. The other recipes of the visir pipeline are [*visir\_img\_dark*(7)](/visir_img_dark/7.md), [*visir\_img\_ff*(7)](/visir_img_ff/7.md), [*visir\_img\_reduce*(7)](/visir_img_reduce/7.md), [*visir\_img\_trans*(7)](/visir_img_trans/7.md), [*visir\_old\_img\_combine*(7)](/visir_old_img_combine/7.md), [*visir\_old\_img\_phot*(7)](/visir_old_img_phot/7.md), [*visir\_old\_spc\_obs*(7)](/visir_old_spc_obs/7.md), [*visir\_old\_spc\_obs\_ech*(7)](/visir_old_spc_obs_ech/7.md), [*visir\_old\_spc\_phot*(7)](/visir_old_spc_phot/7.md), [*visir\_old\_spc\_phot\_ech*(7)](/visir_old_spc_phot_ech/7.md), [*visir\_old\_spc\_wcal*(7)](/visir_old_spc_wcal/7.md), [*visir\_old\_spc\_wcal\_ech*(7)](/visir_old_spc_wcal_ech/7.md), [*visir\_old\_util\_destripe*(7)](/visir_old_util_destripe/7.md), [*visir\_spc\_reduce*(7)](/visir_spc_reduce/7.md), [*visir\_util\_apply\_calib*(7)](/visir_util_apply_calib/7.md), [*visir\_util\_clip*(7)](/visir_util_clip/7.md), [*visir\_util\_convert\_weight*(7)](/visir_util_convert_weight/7.md), [*visir\_util\_detect\_shift*(7)](/visir_util_detect_shift/7.md), [*visir\_util\_img\_std\_cat*(7)](/visir_util_img_std_cat/7.md), [*visir\_util\_join*(7)](/visir_util_join/7.md), [*visir\_util\_qc*(7)](/visir_util_qc/7.md), [*visir\_util\_repack*(7)](/visir_util_repack/7.md), [*visir\_util\_run\_swarp*(7)](/visir_util_run_swarp/7.md), [*visir\_util\_spc\_std\_cat*(7)](/visir_util_spc_std_cat/7.md), [*visir\_util\_spc\_txt2fits*(7)](/visir_util_spc_txt2fits/7.md) ## VERSION visir\_util\_undistort 4.4.2 ## AUTHOR Lars Lundin \ ## BUG REPORTS Please report any problems to https://support.eso.org. Alternatively, you may send a report to the ESO User Support Department \. ## LICENSE This file is part of the VISIR Instrument Pipeline Copyright (C) 2011 European Southern Observatory This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02111-1307 USA